Recording system



April 30, 1940- w. J. ALBERSHEIM 2,198,798

RECORDING SYSTEM Filed Sept. 22, 1958 FIG.

MIXER AMPLIFIER AMPLIFIER I7 5 6 FIG. 2 I 2 22 u/xm VOLUME AMPLIFIER COMPRESSOR E AMPLIFIER a L.n

RECTIFIER FILTER '-"1 f glam/Hm INVL'NTOR By W. J. ALBERSHE/M AT ORNEV Patented Apr. 30, 1940 v j guesses p V RECORDING SYSTEM r Walter J. .Alb'ersheimyGreat Neck, N. Y., as-

signor .to Electrical Research Products, rm,

XNew York, N. Y., a corporation of Delaware Application September 22, meas rial No. 231,150 g o p H 13 Claims. (o nap-100.3) o This invention relates tdsystems for recording by the compressor 3,. which may be a lesser device varyingcurrents upon. a photographic film and such as a simplepotentiometer or variable ree particularly to systemsinjwhich the recording sistance network or a variable gain. device such point is shifted by current from a control circuit. as a variable mu vacuumtubewith a controllable The obj ectof theinvention is a method and grid bias.

.meansof recording a larger range of amplitudes The compressed currents maybe further ami of the varying currents upon aphotographicfilm plified in the amplifier 4 and supplied through within the normal track widt p thewires 5, 6 to a recording device I, Fig. 3, con- A featurejof the invention is a record materially ventionally represented as a two-ribbon variable riarrowerthan the normal track width. density light valve; Any other known type: of .10

Another feature ofthe invention is a record light valve may be used in place of. the. device of the varying currents compressed so that the .shownyand the record may besof the variable amplitude or volume range of the record is less density type or of the variable area type.

than the amplitude or volume range of the" orig- Light from a suitablesource 8 is collected; by p l L inal currentsg j l l Y the lens 9 and collimated by the. lens ID on a 1A further feature of the invention is a record movable mask |l.- The light passingthrough the of constantwidthlaterally displaced inthe track aperture in'the mask II is focussed bylens l2 on in accordance with the degree of compression of the recording device 1, which modulates the light the recorded currents. in accordance with the currents in the wires 5, 6.

i Another feature of the invention is a repro- The modulated light is focussed by the lens I3 29 ducing system in which. the quantity of light en upon the film. While one combination of optical ergy impressed on the photo-electric cell varies elementshas been shown. and described itis aplaterally or the record track. parent that many changes may be made in the These and other features of'the inventionwill optical system withinTthe scope of the invention.

. beapparent to those skilled inthe art from the The control of the compressor 3 is linked to the description set forth hereinafter, and from the control of the variable resistor l4. Current from accompanying drawing, in. which: the battery l5, fiowsi through the variable re- Figll diagrammatically showsa' manually consister M, and Wires l6, IT to the solenoid 18 at-. trolled recording system l l tachedto the movable mask H. The mask II will 1 FiglfZdiagrammaticallyshows an automatically be shifted a distance-proportional to themove- 30 controlled recording system: ment of the controls I4 and 3, that is, proper l ig fi diagrammatically shows the optical portional to the compression of the recorded our tionof the systems of Figs. 1 land .2; rents. Thespring IS restores the mask H toits Fig. 4 :is an enlargedyiew of a portion of the original position when the, electromagnet i8 is filmre cord; deenergized.

5 shows the mask used in the recording The mask H, shown in Fig. 5, has an aperture apparatus; p p Whose image on the film is materially narrower Fig. fipdiagrammatically shows a reproducing than the record track, and for a vertical move- .systemjaand 1 H mentoi the maskil this aperture shifts from one Fig. "Tshows the variation in light transmission 1 side'ofthe track to the other. The aperture may 40 acrojssfthe scanning slit used in the reproducing have straight sides inclined to the axis of the system. c l I .mask, so "that the lateral shift is linearly pro- The microphone i represents. the source of portional to the vertical movement, or thesides' varying currents to be recorded. This source may becurved as shown in Fig. 5fto produce an maybe, as shown, a microphone actuated by arbitrary pr p o ity between the degree of 4 acoustic waves, or any other source. of varying compression and the. lateral shift of the. track. currents such as a disc or film .reproducer, a InFig.,2, thevolume range is automatically radio! receiving set, adetectorf agitated by mecompressed and the mask ll automatically shiftchanical vibrations or any other electrical device ed by a circuit generally similar to the-circuit actuated by any phenomenon to be recorded. I 'he disclosed in U. S.Patent 1,623,756 to C. F. Sacia. varying currents may be amplified in the am- A partof the output cfthe mixer-amplifier 2 is plifier2, which may incorporate means formixamplifiedand rectified in the amplifier-rectifier ing the currents from two or more sources. 20, and the rectified output filtered bythelow-pass Therange of amplitudes or volume of the vary: filter 2 I; A part of the filtered output is supplied ing currents is partially or completely compressed by wires l6, I! to control the solenoid l8, and a ll part controls the volume compressor 22 in circuit between the amplifier 2 and the recording device 1. Any suitable volume compressor may be used, such as the variable amplification device disclosed in the above patent to Sacia or the variable losser devices well known in the communication art.

In Fig. 4, the record 23 is of constant width'and occupies" materially less than the normal width of the track as indicated by the lines 24, 25. The

record 23 is indicated as being shifted from one 1 side of the track to the other. For convenience of illustration, this shift has been made much r In Fig; 6, light from the source 26 is focussed more rapid than would be desirable. In general,

the shift is made quite slowly, rarely more than five times per second, and for sound of constant v volume the record does not shift.

If the record is of the variable density, constant widthtype, the record may be continuously andv proportionately shifted. With records of the variablearea type, better results will'be secured if the record is shifted in a series of steps. In such case the controls 3 and 14 may operate'on terminals tapped off the resistors andthe aper-.

ture in themask II is cut' in steps to correspond.

bythe lenses 2'1, 28 on a scanning slit in the plate 29. The scanning slit covers substantially the full width of the record track on the 'film 3|],that is, the-distance between the lines 24, 25 in Fig. 4; The lighttransmitted through the film excites the photoelectric cell'3i and produces a varying cur- I rent which may beireproduced as sound; may operate-a measuring device or signal; or may be applied toany other desired use. The volume range of the'currents reproduced by such a simple system willof course be compressed and will lack contrast. To expand the volume range, the intensity of the light, must vary laterally of the scanning slit as indicated in Fig. 7. This variation may be produced by an' optical wedge or apertured screen 32 in the optical system, or by the optical stop disclosed in my copending appli-' prises exposing a light sensitive member to a light beam varied in accordance with the soundbeing recorded, reducing the range of the variations of said beam independently of variations in the volume of the sound and varying the lateralposition of said beam with the volume of the sound.

2. The method of recording and reproducing sound which comprises exposing a light sensitive film-to a light beam varied in accordance with the sound being recorded, reducing the range of the variations of said beam independently of varia tions in the, volume of the sound, varying the lateral'position of said beam with the reduction in range of the sound, developing and printing said film, scanning the print Witha beam of light, exciting a light sensitive device withthe light modulated by said record, and varying the quan-- volume consists in tity of light impressed on said device laterally of the film in accordance with the lateral position of said record.

3. Apparatus for recording sound on a photographic film comprising means for converting sound waves into current variations, means for variably amplifying said; variations, means responsive' to ,said variations foncontrolling light impressed on said film, means for laterally shifting the area of said film exposed to said light, and

'a connection between said amplifying means and said shifting means whereby they operate simultaneously. I

4; A film comprising a record of varying currents compressed in amplitude range, of constant width materially less than the width of the record track and-laterally displaced in'the record track in accordance with the degree of compression.

5. A film comprising a variable density sound record of constant-width materially less than, the width. of the record track, laterally displaced in therecord track in accordance with the volumes 6. A film record comprising a sound track-:in which the tone consists of a-constantamplitude variable density record of constantwidth and the a lateral displacement of said tone record. l 7. The method of recording sound which comprises producing a record'of the sound tone being a recorded and. laterally displacing said'rec'ord in accordance with the volumegvariations of said sound.

8. The method of recording prises producing a variable density constantwidth record ofthe sound being recordedQand laterally displacing said record ,in' accordancewiththe average volume of said sound; i.

9. The method of recordingsound-whi'ch coin-1, prises producing a constant amplitude variable area record of the sound being recorded and vary sound which com-1 hum ing the lateral position of said record, inaccordg ance with the amplification necessary to produca said constant amplitude. r 1

10. The method of recording avarying electric current which comprises exposing av light sensitive member toa light beam varied in,acco'rdance with the varying electric current, reducing th'e range of the variations in said beam to lessj than the range, of the variations'in said];v curremki nd varying the lateral position of'said beam with the reduction in the range of variations in 2 said current. r j v I ll. In combination, means for making a photo'- graphic record of a varying 'currentandmeans comprising simultaneously actuatedme'mbers ,for

varying the amplitude of the re'zco-rded variations 13. In combination, means for making a p-ht jtographic record of electrical variations, and-means actuated by said variations for compressing the amplitude range of the recorded variations-and for laterally shifting the record.

v WALTER J. ALBERSHEIM. 

